The fungi of southern Asian are extremely diverse (Hyde et al. 2018, Cheek et al. 2020). During a survey of fungal diversity in ornamental plants in south-western China from 2017 to 2019, more than 2000 strains were obtained, which represented asexual morphs of both Ascomycota and Basidiomycota. Some new taxa were previously described by our research group as pathogens or endophytes (e.g. Liang et al. 2018, Long et al. 2019, Sun et al. 2020, Wijesinghe et al. 2020, Zhang et al. 2020).
Maxtree Plant Models Vol 20
In this paper, we report on Zasmidium species found on medicinal plants in China. One new species (Zasmidium liboense) and one new Chinese record (Z. citri-griseum) are reported, based on evidence from morphology and molecular phylogeny.
All diseased samples were collected from the Medical Plants Herb Garden, in Chongqing City, Nanchuan County, China. This garden is located in a region of subtropical humid monsoon climate and has conserved more than 3000 kinds of medicinal plants. In this study, all fungal strains were isolated by the single-spore technique in order to obtain pure cultures following the method of Chomnunti et al. (2014). Single spores were transferred to potato-dextrose agar (PDA) and incubated at room temperature (28 C). After several weeks of incubation, the morphological characters were recorded following the methods of Manamgoda et al. (2011, 2012). Conidia and conidiophores were observed using a compound microscope (Nikon Eclipse E600 DIC microscope and a Nikon DS-U2 camera or a Nikon 80i compound microscope fitted with a Canon 450D digital camera). The holotype specimen was deposited in the Herbarium of the Department of Plant Pathology, Agricultural College, Guizhou University (HGUP). Ex-type cultures were also deposited in the culture collection at the Department of Plant Pathology, Agriculture College, Guizhou University, P.R. China (GUCC).
Pathogenicity of this species was determined by inoculating healthy leaves of Hippeastrum striatum and Canna indica L. with 5 mm diameter mycelial plugs, cut from the margins of 10-day-old actively growing cultures; the control was treated with sterile agar plugs. Both inoculated and control plants were kept in a moist chamber at 25 C for 7 days and observed for disease symptom development. Infected leaves were collected and the fungus was re-isolated in PDA medium and compared against the original strains. Control plants were sprayed with sterilised distilled water.
Test plants (Hippeastrum striatum) were inoculated with 5 mm diam mycelial plugs of Curvularia microspora with two replicates of each plants and the inoculation experiment was repeated two times (with different sporulation generations). Hippeastrum striatum leaves both exhibited brown to dark brown necrotic spots (Figure 3a, b) after 7 days, which were very similar to those of natural infection (Figure 2a, b). The DNA sequencing result (ITS region), after re-isolation, identified this as C. microspora. The successful re-isolation of C. microspora from the inoculated leaves of H, striatum established a credible proof of pathogenicity. All test plants were covered with polyethylene bags for 7 days. However, on Canna indica, disease symptoms did not appear again.
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